Certain digital data storage applications require storing a large amount of data in an archival storage system. Magnetic disk drives are sometimes used to store the data, for instance, in applications that require the capability of both writing and reading the data. However, in some applications, the volume of data is so immense that the use of magnetic disk drives may be uneconomical, in particular, when the data is suitable for write once data storage applications. Therefore, when a certain application requires storage of a large amount of data, magnetic tape drives have been used in combination with removable tape media. But the data transfer rate to and from the magnetic tape drives is typically significantly lower than that of magnetic disk drives and random access is lacking. Consequently, some systems use optical data storage devices, in combination with removable media, which are quite suitable for write-once-read-many (WORM) data storage applications. The rate of data transfer of optical data storage devices, however, is typically much lower than that of either magnetic disk drives or magnetic tape drives.
Such data storage systems have been accepted in the industry, and they are presumably considered to perform reasonably well for their intended purpose. However, they are not without their shortcomings. For instance, in some applications it is desirable to be able to read/write many times to a memory device and then to transfer this data to an optical storage device, which can improve the archival nature of the stored information.